Method of protecting a radiocommunications terminal against unauthorized use

Abstract

The invention concerns a method of protecting a radiocommunications terminal against unauthorized use, the terminal being adapted to send and receive a plurality of types of user information and a plurality of types of terminal information. According to the invention, when no user information is transmitted, the terminal is automatically switched to a secure mode in which the sending of at least one type of user information is prohibited and the sending of at least one type of terminal information is authorized, secure mode being canceled by entering a predetermined code. The invention applies in particular to GSM mobile terminals.

What is claimed is:  
     
       1. A method of protecting an already initially activated radiocommunications terminal against unauthorized use while keeping the terminal operational, the terminal being adapted to send and receive a plurality of types of user information and a plurality of types of terminal information, said method comprising the steps of: when no user information is transmitted, automatically switching the terminal into a secure mode in which the sending of at least one type of user information is prohibited and the sending of at least one type of terminal information is authorized, and 
       canceling the secure mode by entering a predetermined code.  
     
     
       2. The method according to  claim 1 , wherein the step of automatically switching to the secure mode occurs after a predetermined time-delay. 
     
     
       3. The method according to  claim 1 , wherein the radio-communications terminal includes a display screen, and further comprising the step of deactivating the screen in the secure mode. 
     
     
       4. The method according to  claim 1 , further comprising the steps of: 
       authorizing the receiving by the terminal of an incoming call when the terminal is in the secure mode, and  
       instantaneously switching back to the secure mode at the end of the call.  
     
     
       5. The method according to  claim 1 , further comprising the step of maintaining the terminal in the secure mode if the terminal receives short message service message type user information when the terminal is in secure mode. 
     
     
       6. The method according to  claim 5 , further comprising the steps of: 
       maintaining the terminal in the secure mode, and  
       displaying the received short message service message type user information.  
     
     
       7. The method according to  claim 5 , wherein said terminal includes a display screen, said method further comprising the steps of: 
       storing the short message service message type user information, and  
       maintaining the terminal in the secure mode and the display screen of the terminal in a deactivated state.  
     
     
       8. The method according to  claim 1 , further comprising the step of prohibiting sending of all types of user information in the secure mode. 
     
     
       9. The method according to  claim 1 , further comprising the step of authorizing sending of emergency services call type user information in the secure mode. 
     
     
       10. A radiocommunications terminal adapted to send and receive a plurality of types of user information and a plurality of types of terminal information, the terminal including protection means for protecting the terminal against unauthorized use, while keeping the terminal operational, by implementing a method of protecting an already initially activated radiocommunications terminal against unauthorized use while keeping the terminal operational, said method comprising the steps of: when no user information is transmitted, automatically switching the terminal into a secure mode in which the sending of at least one type of user information is prohibited and the sending of at least one type of terminal information is authorized, and canceling the secure mode by entering a predetermined code, the protection means comprising: 
       switch means for switching the terminal automatically to said secure mode in which the sending of at least one type of user information is prohibited and the sending of at least one type of terminal information is authorized, and  
       activatable cancellation means for canceling the secure mode.  
     
     
       11. The terminal according to  claim 10 , further comprising means for activating the cancellation means by entering the predetermined code.